by Kira Harvey
What kind of disturbance creates an electromagnetic wave?
How are electromagnetic waves different from mechanical waves?
What is the Electromagnetic Spectrum?
Infrared wavelengths span from 710 nm – 1 millimeter (from the width of a pinpoint to the size of small plant seeds). At a temperature of 37 degrees C, our bodies give off infrared wavelengths with a peak intensity near 900 nm. Infrared is used in night vison goggles and in space it helps us map the dust between stars.
Visible light covers the range of wavelengths from 400 – 700 nm (from the size of a molecule to a protozoan). Our sun emits the most of its radiation in the visible range, which our eyes perceive as the colors of the rainbow. Light bulbs and rainbows are example of visible light.
Ultraviolet radiation has wavelengths of 10 – 310 nm (about the size of a virus). Ultraviolet radiation comes from the sun and is used in tanning beds.
Gamma rays have the shortest wavelengths, < 0.01 nanometers (about the size of an atomic nucleus). This is the highest frequency and most energetic region of the electromagnetic spectrum. They are used by doctors to see inside of the body and black holes.